/*
** $Id: lbaselib.c,v 1.314 2016/09/05 19:06:34 roberto Exp $
** Basic library
** See Copyright Notice in lua.h
*/

#define lbaselib_c
#define LUA_LIB

#include "lprefix.h"


#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


static int luaB_print(lua_State *L)
{
    int n = lua_gettop(L);  /* number of arguments */
    int i;
    lua_getglobal(L, "tostring");

    for (i = 1; i <= n; i++)
    {
        const char *s;
        size_t l;
        lua_pushvalue(L, -1);  /* function to be called */
        lua_pushvalue(L, i);   /* value to print */
        lua_call(L, 1, 1);
        s = lua_tolstring(L, -1, &l);  /* get result */

        if (s == NULL)
            return luaL_error(L, "'tostring' must return a string to 'print'");

        if (i > 1) lua_writestring("\t", 1);

        lua_writestring(s, l);
        lua_pop(L, 1);  /* pop result */
    }

    lua_writeline();
    return 0;
}


#define SPACECHARS  " \f\n\r\t\v"

static const char *b_str2int(const char *s, int base, lua_Integer *pn)
{
    lua_Unsigned n = 0;
    int neg = 0;
    s += strspn(s, SPACECHARS);  /* skip initial spaces */

    if (*s == '-')
    {
        s++;    /* handle signal */
        neg = 1;
    }
    else if (*s == '+') s++;

    if (!isalnum((unsigned char)*s))  /* no digit? */
        return NULL;

    do
    {
        int digit = (isdigit((unsigned char) * s)) ? *s - '0'
                    : (toupper((unsigned char) * s) - 'A') + 10;

        if (digit >= base) return NULL;  /* invalid numeral */

        n = n * base + digit;
        s++;
    } while (isalnum((unsigned char)*s));

    s += strspn(s, SPACECHARS);  /* skip trailing spaces */
    *pn = (lua_Integer)((neg) ? (0u - n) : n);
    return s;
}


static int luaB_tonumber(lua_State *L)
{
    if (lua_isnoneornil(L, 2))    /* standard conversion? */
    {
        luaL_checkany(L, 1);

        if (lua_type(L, 1) == LUA_TNUMBER)    /* already a number? */
        {
            lua_settop(L, 1);  /* yes; return it */
            return 1;
        }
        else
        {
            size_t l;
            const char *s = lua_tolstring(L, 1, &l);

            if (s != NULL && lua_stringtonumber(L, s) == l + 1)
                return 1;  /* successful conversion to number */

            /* else not a number */
        }
    }
    else
    {
        size_t l;
        const char *s;
        lua_Integer n = 0;  /* to avoid warnings */
        lua_Integer base = luaL_checkinteger(L, 2);
        luaL_checktype(L, 1, LUA_TSTRING);  /* no numbers as strings */
        s = lua_tolstring(L, 1, &l);
        luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");

        if (b_str2int(s, (int)base, &n) == s + l)
        {
            lua_pushinteger(L, n);
            return 1;
        }  /* else not a number */
    }  /* else not a number */

    lua_pushnil(L);  /* not a number */
    return 1;
}


static int luaB_error(lua_State *L)
{
    int level = (int)luaL_optinteger(L, 2, 1);
    lua_settop(L, 1);

    if (lua_type(L, 1) == LUA_TSTRING && level > 0)
    {
        luaL_where(L, level);   /* add extra information */
        lua_pushvalue(L, 1);
        lua_concat(L, 2);
    }

    return lua_error(L);
}


static int luaB_getmetatable(lua_State *L)
{
    luaL_checkany(L, 1);

    if (!lua_getmetatable(L, 1))
    {
        lua_pushnil(L);
        return 1;  /* no metatable */
    }

    luaL_getmetafield(L, 1, "__metatable");
    return 1;  /* returns either __metatable field (if present) or metatable */
}


static int luaB_setmetatable(lua_State *L)
{
    int t = lua_type(L, 2);
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
                  "nil or table expected");

    if (luaL_getmetafield(L, 1, "__metatable") != LUA_TNIL)
        return luaL_error(L, "cannot change a protected metatable");

    lua_settop(L, 2);
    lua_setmetatable(L, 1);
    return 1;
}


static int luaB_rawequal(lua_State *L)
{
    luaL_checkany(L, 1);
    luaL_checkany(L, 2);
    lua_pushboolean(L, lua_rawequal(L, 1, 2));
    return 1;
}


static int luaB_rawlen(lua_State *L)
{
    int t = lua_type(L, 1);
    luaL_argcheck(L, t == LUA_TTABLE || t == LUA_TSTRING, 1,
                  "table or string expected");
    lua_pushinteger(L, lua_rawlen(L, 1));
    return 1;
}


static int luaB_rawget(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_checkany(L, 2);
    lua_settop(L, 2);
    lua_rawget(L, 1);
    return 1;
}

static int luaB_rawset(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_checkany(L, 2);
    luaL_checkany(L, 3);
    lua_settop(L, 3);
    lua_rawset(L, 1);
    return 1;
}


static int luaB_collectgarbage(lua_State *L)
{
    static const char *const opts[] = {"stop", "restart", "collect",
                                       "count", "step", "setpause", "setstepmul",
                                       "isrunning", NULL
                                      };
    static const int optsnum[] = {LUA_GCSTOP, LUA_GCRESTART, LUA_GCCOLLECT,
                                  LUA_GCCOUNT, LUA_GCSTEP, LUA_GCSETPAUSE, LUA_GCSETSTEPMUL,
                                  LUA_GCISRUNNING
                                 };
    int o = optsnum[luaL_checkoption(L, 1, "collect", opts)];
    int ex = (int)luaL_optinteger(L, 2, 0);
    int res = lua_gc(L, o, ex);

    switch (o)
    {
        case LUA_GCCOUNT:
        {
            int b = lua_gc(L, LUA_GCCOUNTB, 0);
            lua_pushnumber(L, (lua_Number)res + ((lua_Number)b / 1024));
            return 1;
        }

        case LUA_GCSTEP:
        case LUA_GCISRUNNING:
        {
            lua_pushboolean(L, res);
            return 1;
        }

        default:
        {
            lua_pushinteger(L, res);
            return 1;
        }
    }
}


static int luaB_type(lua_State *L)
{
    int t = lua_type(L, 1);
    luaL_argcheck(L, t != LUA_TNONE, 1, "value expected");
    lua_pushstring(L, lua_typename(L, t));
    return 1;
}


static int pairsmeta(lua_State *L, const char *method, int iszero,
                     lua_CFunction iter)
{
    luaL_checkany(L, 1);

    if (luaL_getmetafield(L, 1, method) == LUA_TNIL)    /* no metamethod? */
    {
        lua_pushcfunction(L, iter);  /* will return generator, */
        lua_pushvalue(L, 1);  /* state, */

        if (iszero) lua_pushinteger(L, 0);  /* and initial value */
        else lua_pushnil(L);
    }
    else
    {
        lua_pushvalue(L, 1);  /* argument 'self' to metamethod */
        lua_call(L, 1, 3);  /* get 3 values from metamethod */
    }

    return 3;
}


static int luaB_next(lua_State *L)
{
    luaL_checktype(L, 1, LUA_TTABLE);
    lua_settop(L, 2);  /* create a 2nd argument if there isn't one */

    if (lua_next(L, 1))
        return 2;
    else
    {
        lua_pushnil(L);
        return 1;
    }
}


static int luaB_pairs(lua_State *L)
{
    return pairsmeta(L, "__pairs", 0, luaB_next);
}


/*
** Traversal function for 'ipairs'
*/
static int ipairsaux(lua_State *L)
{
    lua_Integer i = luaL_checkinteger(L, 2) + 1;
    lua_pushinteger(L, i);
    return (lua_geti(L, 1, i) == LUA_TNIL) ? 1 : 2;
}


/*
** 'ipairs' function. Returns 'ipairsaux', given "table", 0.
** (The given "table" may not be a table.)
*/
static int luaB_ipairs(lua_State *L)
{
#if defined(LUA_COMPAT_IPAIRS)
    return pairsmeta(L, "__ipairs", 1, ipairsaux);
#else
    luaL_checkany(L, 1);
    lua_pushcfunction(L, ipairsaux);  /* iteration function */
    lua_pushvalue(L, 1);  /* state */
    lua_pushinteger(L, 0);  /* initial value */
    return 3;
#endif
}


static int load_aux(lua_State *L, int status, int envidx)
{
    if (status == LUA_OK)
    {
        if (envidx != 0)    /* 'env' parameter? */
        {
            lua_pushvalue(L, envidx);  /* environment for loaded function */

            if (!lua_setupvalue(L, -2, 1))  /* set it as 1st upvalue */
                lua_pop(L, 1);  /* remove 'env' if not used by previous call */
        }

        return 1;
    }
    else    /* error (message is on top of the stack) */
    {
        lua_pushnil(L);
        lua_insert(L, -2);  /* put before error message */
        return 2;  /* return nil plus error message */
    }
}


static int luaB_loadfile(lua_State *L)
{
    const char *fname = luaL_optstring(L, 1, NULL);
    const char *mode = luaL_optstring(L, 2, NULL);
    int env = (!lua_isnone(L, 3) ? 3 : 0);  /* 'env' index or 0 if no 'env' */
    int status = luaL_loadfilex(L, fname, mode);
    return load_aux(L, status, env);
}


/*
** {======================================================
** Generic Read function
** =======================================================
*/


/*
** reserved slot, above all arguments, to hold a copy of the returned
** string to avoid it being collected while parsed. 'load' has four
** optional arguments (chunk, source name, mode, and environment).
*/
#define RESERVEDSLOT    5


/*
** Reader for generic 'load' function: 'lua_load' uses the
** stack for internal stuff, so the reader cannot change the
** stack top. Instead, it keeps its resulting string in a
** reserved slot inside the stack.
*/
static const char *generic_reader(lua_State *L, void *ud, size_t *size)
{
    (void)(ud);  /* not used */
    luaL_checkstack(L, 2, "too many nested functions");
    lua_pushvalue(L, 1);  /* get function */
    lua_call(L, 0, 1);  /* call it */

    if (lua_isnil(L, -1))
    {
        lua_pop(L, 1);  /* pop result */
        *size = 0;
        return NULL;
    }
    else if (!lua_isstring(L, -1))
        luaL_error(L, "reader function must return a string");

    lua_replace(L, RESERVEDSLOT);  /* save string in reserved slot */
    return lua_tolstring(L, RESERVEDSLOT, size);
}


static int luaB_load(lua_State *L)
{
    int status;
    size_t l;
    const char *s = lua_tolstring(L, 1, &l);
    const char *mode = luaL_optstring(L, 3, "bt");
    int env = (!lua_isnone(L, 4) ? 4 : 0);  /* 'env' index or 0 if no 'env' */

    if (s != NULL)    /* loading a string? */
    {
        const char *chunkname = luaL_optstring(L, 2, s);
        status = luaL_loadbufferx(L, s, l, chunkname, mode);
    }
    else    /* loading from a reader function */
    {
        const char *chunkname = luaL_optstring(L, 2, "=(load)");
        luaL_checktype(L, 1, LUA_TFUNCTION);
        lua_settop(L, RESERVEDSLOT);  /* create reserved slot */
        status = lua_load(L, generic_reader, NULL, chunkname, mode);
    }

    return load_aux(L, status, env);
}

/* }====================================================== */


static int dofilecont(lua_State *L, int d1, lua_KContext d2)
{
    (void)d1;
    (void)d2;  /* only to match 'lua_Kfunction' prototype */
    return lua_gettop(L) - 1;
}


static int luaB_dofile(lua_State *L)
{
    const char *fname = luaL_optstring(L, 1, NULL);
    lua_settop(L, 1);

    if (luaL_loadfile(L, fname) != LUA_OK)
        return lua_error(L);

    lua_callk(L, 0, LUA_MULTRET, 0, dofilecont);
    return dofilecont(L, 0, 0);
}


static int luaB_assert(lua_State *L)
{
    if (lua_toboolean(L, 1))  /* condition is true? */
        return lua_gettop(L);  /* return all arguments */
    else    /* error */
    {
        luaL_checkany(L, 1);  /* there must be a condition */
        lua_remove(L, 1);  /* remove it */
        lua_pushliteral(L, "assertion failed!");  /* default message */
        lua_settop(L, 1);  /* leave only message (default if no other one) */
        return luaB_error(L);  /* call 'error' */
    }
}


static int luaB_select(lua_State *L)
{
    int n = lua_gettop(L);

    if (lua_type(L, 1) == LUA_TSTRING && *lua_tostring(L, 1) == '#')
    {
        lua_pushinteger(L, n - 1);
        return 1;
    }
    else
    {
        lua_Integer i = luaL_checkinteger(L, 1);

        if (i < 0) i = n + i;
        else if (i > n) i = n;

        luaL_argcheck(L, 1 <= i, 1, "index out of range");
        return n - (int)i;
    }
}


/*
** Continuation function for 'pcall' and 'xpcall'. Both functions
** already pushed a 'true' before doing the call, so in case of success
** 'finishpcall' only has to return everything in the stack minus
** 'extra' values (where 'extra' is exactly the number of items to be
** ignored).
*/
static int finishpcall(lua_State *L, int status, lua_KContext extra)
{
    if (status != LUA_OK && status != LUA_YIELD)    /* error? */
    {
        lua_pushboolean(L, 0);  /* first result (false) */
        lua_pushvalue(L, -2);  /* error message */
        return 2;  /* return false, msg */
    }
    else
        return lua_gettop(L) - (int)extra;  /* return all results */
}


static int luaB_pcall(lua_State *L)
{
    int status;
    luaL_checkany(L, 1);
    lua_pushboolean(L, 1);  /* first result if no errors */
    lua_insert(L, 1);  /* put it in place */
    status = lua_pcallk(L, lua_gettop(L) - 2, LUA_MULTRET, 0, 0, finishpcall);
    return finishpcall(L, status, 0);
}


/*
** Do a protected call with error handling. After 'lua_rotate', the
** stack will have <f, err, true, f, [args...]>; so, the function passes
** 2 to 'finishpcall' to skip the 2 first values when returning results.
*/
static int luaB_xpcall(lua_State *L)
{
    int status;
    int n = lua_gettop(L);
    luaL_checktype(L, 2, LUA_TFUNCTION);  /* check error function */
    lua_pushboolean(L, 1);  /* first result */
    lua_pushvalue(L, 1);  /* function */
    lua_rotate(L, 3, 2);  /* move them below function's arguments */
    status = lua_pcallk(L, n - 2, LUA_MULTRET, 2, 2, finishpcall);
    return finishpcall(L, status, 2);
}


static int luaB_tostring(lua_State *L)
{
    luaL_checkany(L, 1);
    luaL_tolstring(L, 1, NULL);
    return 1;
}


static const luaL_Reg base_funcs[] =
{
    {"assert", luaB_assert},
    {"collectgarbage", luaB_collectgarbage},
    {"dofile", luaB_dofile},
    {"error", luaB_error},
    {"getmetatable", luaB_getmetatable},
    {"ipairs", luaB_ipairs},
    {"loadfile", luaB_loadfile},
    {"load", luaB_load},
#if defined(LUA_COMPAT_LOADSTRING)
    {"loadstring", luaB_load},
#endif
    {"next", luaB_next},
    {"pairs", luaB_pairs},
    {"pcall", luaB_pcall},
    {"print", luaB_print},
    {"rawequal", luaB_rawequal},
    {"rawlen", luaB_rawlen},
    {"rawget", luaB_rawget},
    {"rawset", luaB_rawset},
    {"select", luaB_select},
    {"setmetatable", luaB_setmetatable},
    {"tonumber", luaB_tonumber},
    {"tostring", luaB_tostring},
    {"type", luaB_type},
    {"xpcall", luaB_xpcall},
    /* placeholders */
    {"_G", NULL},
    {"_VERSION", NULL},
    {NULL, NULL}
};


LUAMOD_API int luaopen_base(lua_State *L)
{
    /* open lib into global table */
    lua_pushglobaltable(L);
    luaL_setfuncs(L, base_funcs, 0);
    /* set global _G */
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, "_G");
    /* set global _VERSION */
    lua_pushliteral(L, LUA_VERSION);
    lua_setfield(L, -2, "_VERSION");
    return 1;
}

